There is a discharge surface treatment technique in which a film is formed on a surface of a workpiece using a discharge surface treatment electrode. In Patent Literature 1, a green compact obtained by compacting a powder inside a mold, a sintered compact obtained by sintering a green compact, or a calcined compact obtained by calcining a green compact is used for a discharge surface treatment electrode. In a discharge surface treatment technique using a discharge surface treatment electrode, the discharge surface treatment electrode is caused to face a workpiece and a discharge phenomenon is generated between the discharge surface treatment electrode and the workpiece. A powder collapses from the discharge surface treatment electrode and floats due to the discharge explosive force of the discharge phenomenon. Then, the floating powder is melted and solidified on the surface of the workpiece, and a film is thereby formed on the surface of the workpiece.
In the discharge surface treatment electrode, it is necessary for a powder to collapse due to the discharge explosive force. Thus, in the discharge surface treatment electrode, it is necessary to provide a certain distance between powder particles forming the discharge surface treatment electrode, i.e., to control the porosity of the discharge surface treatment electrode.